RE: Bless This house.
You should remember that many buildings have a threshold...the threshold just happens to be 0. So, for instance, an office might have a threshold, or a factory lunch room etc...As soon as someone with Bless This House walks in, suddenly your threshold is boosted to 2. That is 2 refresh worth of powers removed from anyone not invited.
That said, there is a couple of custom powers. I made one called "Home is Where I Hang My Hat"
Essentially, given time to prepare, you can create a threshold as long as you have some line to call a threshold. The idea was that it was an outdoorsy campaign so my character could turn the light from a campfire in to a threshold.
So, he hangs the Rosary over the door of room and that room is protected. Or hangs it from a tree in a meadow and the meadow is protected. The scope of the power covered, roughly, one zone. I forget what the Power of the threshold was. If I can find the power, I'll post it.
The other option is this:
"Using conviction, you create a block in the zone you are standing"
This isn't too overpowered. Basically, it just lets you do a regular Block that lasts one round. You state what you are blocking (movement in and out of the zone, attacks while in the zone etc...), you roll conviction and your result is the Power of the Block and it lasts one round or until it is overcome.
You can practically do that with any skill without spending a FP or refresh anyways. I mean, if I wanted, I could make an intimidation block on movement with the fluff being: "I'm so scary no one will move towards me." Of course, it won't prevent them from shooting me with guns, but still.
In any case, that might cost 1 refresh...if you want it to block multiple actions simultaneously, it might cost more...but, for a power that requires an action and only one turn, I might let it only cost 1 refresh.
Sanctaphrax is good at judging game balance...maybe he will give his 2 cents.